Magnetic temperature regulator



Patented Jan. 10, 1928.

' UNITED STATES PATENT OFFICE.

ARTHUR. HERMAN ADAMS, or LA GRANGE, ILLINOIS, AssIeNon To wEsTEnN ELEC-TnIcvcoirPANY, INconronATEn, or NEW YORK, N. Y., A coaPoaATioN or NEwYORK.

Application led January 2, 192B, Serial No. 79,047. Renewed July 20,1927.

This invention relates to magnetic temperature regulators and moreparticularly to devices of the above character which respond to changesin temperature for controlling an I electrical circuit and which controlthe temperature and vice versa. i

The principal object of the invention 1s to provide a magneticallycontrolled temperature responsive device operative due to variations intemperatures for controlling an electrical circuit.

In accordance with one embodiment, the invention contemplates `amagnetic control means operative responsive to temperature changes inwhich a metal of the nickel-iron series is utilized as a part of themagnetic circuit and which nickel-iron metal is affected by temperaturevariations to cause operative response of the magnetic control means forcontrolling or regulating electrical circuits or other apparatus such asthat which produces the temperature.

The various features of the invention will be pointed out moreparticularly in the speciiication and appended claims.

For a better understanding of the invention reference is to be had tothe accompanyin drawing, in which g. l shows the invention applied for3u regulating the temperature of a metal bath;

Fig. 2 shows the invention apphed to a flasher circuit, and

Fig. 3 shows the invention applied as a safety device to an electricalfiat iron to prea5 vent the overheating of the iron.

Referring now more in detail to the arrangement shown in Fig. 1, asuitable receptacle 5 is provided for holding a metal bath 6 such as tinor solder and which receptacle 4o and bath are heated by a suitableresistor or heating element 7 shown as operated from a source ofelectrical current 8.

In the arrangement shown in Fig. 1 .the temperature of the bath ismaintained within upper and lower limits b a magnetic control meanswhich is responsive to the temperature changes of the bath, this controlmeans including a suitable magnet 9 which may be a permanent magnet incase the temperatures to which it is subjected are suiiiciently low sothat its permanence will not be deleteriously affected thereby, having asoft iron pole piece 10-1which extends up into the bath so as to conductthe magnetic hnes of force from the magnet 9 to the armature the circuitto the resistor when the armature A is attracted and released. A portionof the armature A extends into the bath 6 so that it will be heatedthereby.

.This armature A is made of a metal of the nickel-iron series and of acomposition of these two metals which will lose its ferromagnetism ornormal permeability when it reaches a predetermined criticaltemperature, but will regain ferro-magnetism or normal permeability whencooled to another predetermined critical temperature. Thus so long asthe armature A is below its critical temperature the magnetism from themagnet 9 will hold it attracted to the pole piece 10, but upon reachingthe critical point it is released or retracted and moves against theback-stop 13 which may be of suitable metal to speed the cooling of thearmature. This back-stop may be of copper, or it may consist of a wetwick or other means so that the armature will quickly cool until itregains its normal permeability and be drawn into the bath by the magnetbefore the bath has had time to cool more than the predetermined amount.

The armature A is retracted by a spring 14 and its retraction may belimited by a back-stop screw 15. Of course,.if desired the armature maybe made of a balanced structure or lifted out of the bath in any of theWell known ways.

The portion of the armature A which is affected by the heat of the bathshould be of small mass and designed so as to be heated quickly by thebath and also quickly cooled, thereby securing a sensitive control ofthe temperature.

For a control device such as in Fig. 1 a nickel-iron element isemployed, preferably composed of 45% nickel and 55% iron and adjusted sothat operations within a close range are obtained. That is, assuming thebath 6 is at a temperature below the critical temperature at which thearmature A loses its normal permeability, at this time the current is onthe heating element 7. Therefore the temperature of the bath and theimmersed armature A continues to increase,

and when the temperature of the armature A reaches that at which itloses its normal permeability the armature is released and opens theheating circuit. The armature now begins to cool, also the bath, andwhen the temperature of the armature drops, say for the purpose` ofillustration somewhere between 40 and 50 degrees F., its othercriticalpoint is reached where it regains its normal permeability and it isimmedlately attracted by the magnetl to close the heating circuit. Inthefmeantime the bath may have cooled only four or live degrees,depending upon relative mass and heat dissipating conditions of the bathand armature. It will thus be seen that the armature may be attractedand released to close and open the heating circuit and maintain the bathas closely as may be desired at a certain maximum temperature. That is,there is a reiiex action in which when the current is on, thetemperature of the bath and armature is increased until the uppercritical temperature of the armature is reached and the circuitinterrupted, and then the temperature of the armature decreases untilthe armature, outside the bath, is cooled to its lower criticaltemperature to again close the heating circuit, this action continuingso long as current is connected to the device.

' It will be evident that due to the rapid cooling of the armatureoutside of the bath, the armature is redrawn into the bath beforesuilicient time has elapsed for the bath to cool appreciably. In otherwords, the armature repeatedly tests the bath to determine itstemperature. Whenever in making such tests the temperature of the bathis found to be slightly less than the temperature at which 1t is desiredto maintain it, the heatingr element is connected with the source ofcurrent for raising the temperature of the bath to that desired. Thusthe temperature of the bath is controlled within very much closer limitsthan those existing between the two critical temperatures mentioned ofthe particular alloy employed in the armature.

In Fig. 2 the invention is applied to a flasher circuit, that is, acircuit adapted for flashing a series of lamps, although of course thedevice may be used for the many other purposes for which such flashersare employed. In this modification the heating element is applieddirectly as a winding on nickel-iron elements and in which is provided amagnet 16, preferably an electromagnet having a winding 17 in circuitwith a source of current 18. The core ends of the magnet 16 have polarextensions 19-20 which compose the nickel-iron portion of the magneticcircuit for controlling the armature therein. On these nickel-iron polarextensions 19-20 heating windings 21-22 are applied which may be woundeither to 24 which is connected in circuit with the device to beoperated, in the present instance a seriesof lamps 25. However thearma.- ture, any other portion or all portions of the magnetic circuitmay be made of nickeliron, the heating windings being applied to thenickel-iron portion or ortions.

In the operation of the evice of'F ig. 2, when the switch 26 is closed acircuit is established through the winding 17 to establish a magneticcircuit including core 16, pole extensions 19-20 and armature 24, andassuming that the nickel-iron pole extensions 21--22 are at this time ata temperature at which the nickel-iron possesses its normalpermeability, armature 24 is attracted to close the circuit through theheating windings 21-22 and the lamps 25. The flow of current through thewindings 21-22 therefore heats the pole extensions 19-20 until theyreach a temperature where the nickeliron loses its normal permeability.Armature 24 is therefore released to open the circuit of the heatingwindings and also o the lamps 25. The pole extensions 19-20 now begin tocool and when the temperature has dropped to a point where thenickeliron regains its normal permeability the armature is againattracted to close the circuit for the heating windings and also for thelamps 25 until the pole pieces are heated suiiiciently to effectretraction of the armature again. Thus this reflex action continues solongas current is supplied to the device. Although the heating windingsare shown connected in circuit with the lamps 25, it will be apparentthat other arrangements may be used such as having the heating windingsand lamp connected in separate paths, so that each will'havc its owncircuit. It is to be understood that these heating windings 21-22 may bearranged according to the operation desired, and likewise the mass andheat dissipating features and the nickel-iron percentages of the poleextensions 19-20 may be widely varied depending upon the operationdesired, and so as to secure fast or slow operations.

In Fig. 3 is shown another modification of my invention, in which thenickel-iron element is used as a portion of a magnetic circuit acting asa safety device for an electric flat iron so as to prevent overheatingof the iron when not being used. In this device the usual heatingelement 27 is employed for heating the flat iron and in the safetydevice a magnetic circuit is employed including a nickel-iron elementaffected by the heating of the iron to release an armature to open thecircuit of the heating element.

In the arrangement shown an electromagnet is employed having a core 2 8and armature 29 connected to the power terminal 30 and adapted to closea circuit'through contact 31 so as to connect the iron heating element27 in circuit and also the magnet Winding 32. -The armature circuit is 1nitially closed by pressing a button 33 which moves the armature to thec ore to close the contact 31, thereby energizing the magnet to hold thearmature and therebymaintain the circuit through the heating element 27closed. The temperature of the iron then increases and the nickel-ironelement of the magnetic circuit becomes heated from the heat of the.iron. The parts are preferably so arranged that so lon as the iron isbeing used, enough heat is dissipated to keep the nickel-iron elementbelow its upper critical temperature, that is, at a temperature Where itretains its'magnetic conductive quality. But should the iron be leftstanding without use and with the current on, the iron will heatcumulatively so as to increase the temperature of the nickel-ironelement in the magnetic circuit to its upper critical temperature Whereit loses its normal permeability'. The armature is thereupon released toopen the circuit, remaining open until the button 33 is again actuated.It will be noted that the armature will not remain in its attractedposition if the button is actuated while the temperature of the iron isexcessive.

In the magnetic circuit of Fig. 3, the armature A is shown made of thenickeliron alloy, although it Will be apparent that the nickel-iron maybe placed in an part of the magnetic circuit. It Woul almost equallyWell interrupt the magnetic flux to release the armature, when itstemperature becomes that at which the nickel-iron loses its normalpermeability, if it constituted the core or the pole piece, or anyreasonably large portion of the magnetic circuit.

lVhat is claimed is:

l. In a control device, a magnetic control means operatively responsiveto temperature changes in which a metal of the nickel-iron series isutilized as a part of the magnetic circuit, the magnetic permeability ofthe nickel-iron part responsive to temperature variations to causeoperative response of the magnetic control means.

2. In a control device, a magnetic circuit, including a magnet andcooperating armature, and in which a .metal of the nickel-iron series isused as a part of the magnetic circuit, the magnetic permeability of thenickel-iron part responsive to temperature changes to cause operation ofthe armature.

3. In a control device, a magnetic circuit including a magnet andcooperating armature and in which a metal of the nickel-iron series isused as a part of the magnetic circuit, the magnetic permeability of thenickel-iron part responsive-to temperature changes to cause operation ofthe armature, and an electric circuit controlled by the armature forcausing such temperature changes to elect said operation of thearmature.

4. In a control device, a magnetic circuit including a magnet andcooperatin ture and in which a metal of the nic el-iron series is usedas a part of the magnetic circuit, the magnetic permeability of thenickeliron part responsive to temperature changes to cause operation ofthe armature, and an electric circuit including a heating elementcontrolled by the armature for causing such temperature changes to eiectsaid operation of the armature.

5. In a control device, a magnetic circuit including a magnet andcooperating armature and in which a metal of the nickel-iron series isused as a part ofthe magnetic circuit, the magnetic permeability of thenickeliron part responsive to temperature changes to eii'ect attractionand release of the armature, said armature being attracted to saidmagnet, and a heating element included in a circuit closed by theattracted armature for raising the temperature of the nickel-iron toeffect a release of the armature.

. 6. In a control device, a magnetic circuit, including a magnet andcooperatin armature, in which a metal of the nic el-iron series is usedas a part of the magnetic circuit, the magnetic permeability of thenickeliron part responsive to temperature changes to vary the magneticcircuit to eiect attraction and release of the armature.

7. In a control device, a circuit in which a metal element of thenickel-iron series is included as a part of the magnetic circuit, acircuit control device actuated by a change in temperature of thenickel-iron element, and a circuit controlled by said device foreffecting a temperature change of the nickeliron element.

8. In a control device, a magnetic circuit in which a metal element ofthe nickel-iron series is included as a part, an armature in saidmagnetic circuit operatively responsive to a change in temperature ofthe nickel-iron element, and a circuit controlled by said armature foreffecting a temperature change of the nickel-iron element. i

9. In a temperature control device, a magnetic control means includingan armature and in which a metal of the nickel-iron series is utilizedas a part of the magnetic structure and is responsive to temperaturevariations to attract and to release the armature, an electric circuitcontrolled by the armature having a reflex action for controlling thecircuit by raising the temperature of the nickelarmairon part 'to affectthe magnetic structureso as to release the attracted armature to1nterrupt the electric circuit thereby lowering the temperature of thenickel-iron part to cause attraction of the armature to again close thecircuit to raise the temperature, such reflex operations automatically continuing While current is supplied to the electric circuit.

10. In a magnetic temperature regulator, a magnetic circuit including amagnet and cooperating armature in which a part of the' magnetic circuitis responsive to temperature changes of substantially separated lowerand upper temperature limits to cause said part to possess and lose itsnormal magnetic permeability to cause attraction and release of themagnet and armature, a heated mass from which said metal part is heated,and means for maintaining the temperature of said heated mass within asubstantially closer range than that between said lower and uppertemperature limits.

11. In a temperature regulator for a heated mass, a temperatureproducing means for heating the mass, a magnetic circuit including amagnet and a cooperating armat-ure and in which a part of the magneticcircuit is responsive to temperature changes of substantially separatedlower and upper temperature limits to cause said part to possess andlose its normal magnetic permeability to attract 4the armature intoaposition wherein it is subjected to the heat of the mass, said armaturereleasing when attaining its said upper limit of temperature to i'enderthe temperature producing means ineffective to cat the mass, and meansfor transferring the released armature into a cooler region wherein itregains its normal magnetic permeability before the mass has cooled acorresponding amount, thereby becoming reattracted to render-thetemperature producing means eil'ective for heating the mass.

l2. In a temperature regulator for a heated mass, a circuit closercontrolling the application of heat to the mass, an armature of magneticmaterial which loses its normal magnetic permeability at a desiredtemperature, said' armature controlling said circuit closer, a magnetfor attracting said armature into a position relative to the heated masswherein a portion of said armature is heated to the desired temperature,and a restoring means for thereupon transferrin the armature intoanother position to coo the armature whereby it regains its normalmagnetic permeability.

In Witness whereof, I hereunto subscribe my name this 18th day ofDecember, A. D 1925.

ARTHUR HERMAN ADAMS.

